294 research outputs found

    ParFORM: recent development

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    We report on the status of our project of parallelization of the symbolic manipulation program FORM. We have now parallel versions of FORM running on Cluster- or SMP-architectures. These versions can be used to run arbitrary FORM programs in parallel.Comment: 5 pages, 6 Encapsulated postscript figures, LaTeX2e, uses espcrc2.sty (included). Talk given at ACAT0

    Cloning and sequencing the urocanase gene (hutU) from Pseudomonas putida

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    AbstractA clone harbouring the entire urocanase gene (hutU) was obtained from a genomic library of Pseudomonas putida using oligonucleotide probes synthesised on the basis of known flanking sequences. One subunit of urocanase consists of 556 amino acids and has a molecular mass of 60 771 Da

    Limits on Lorentz Violation from the Highest Energy Cosmic Rays

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    We place several new limits on Lorentz violating effects, which can modify particles' dispersion relations, by considering the highest energy cosmic rays observed. Since these are hadrons, this involves considering the partonic content of such cosmic rays. We get a number of bounds on differences in maximum propagation speeds, which are typically bounded at the 10^{-21} level, and on momentum dependent dispersion corrections of the form v = 1 +- p^2/Lambda^2, which typically bound Lambda > 10^{21} GeV, well above the Planck scale. For (CPT violating) dispersion correction of the form v = 1 + p/Lambda, the bounds are up to 15 orders of magnitude beyond the Planck scale.Comment: 24 pages, no figures. Added references, very slight changes. Version published in Physical Review

    Order αs2\alpha_s^2 perturbative QCD corrections to the Gottfried sum rule

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    The order αs2\alpha_s^2 perturbative QCD correction to the Gottfried sum rule is obtained. The result is based on numerical calculation of the order αs2\alpha_s^2 contribution to the coefficient function and on the new estimate of the three-loop anomalous dimension term. The correction found is negative and rather small. Therefore it does not affect the necessity to introduce flavour-asymmetry between uˉ\bar{u} and dˉ\bar{d} antiquarks for the description of NMC result for the Gottfried sum rule.Comment: LaTeX, 7 pages, the discussions of the αs2\alpha_s^2 corrections to the anomalous dimension are modified; 1 reference added; to be published in Phys. Lett.

    Higgs Boson Production at Hadron Colliders

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    I report on a calculation of the inclusive Higgs boson production cross section at hadron colliders at next-to-next-to-leading order in QCD. The result is computed as an expansion about the threshold region. By continuing the expansion to very high order, we map the result onto basis functions and obtain the result in closed analytic form.Comment: 3 pages, 2 figures, uses espcrc2.sty. Talk presented at XXXIst International Conference on High Energy Physics, Amsterdam, The Netherlands, 24-31 July, 200

    alpha_s^3 conversion relation betweeen MS-bar and Euclidean quark masses

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    We report on the analytical calculation of NNNLO (of order alpha_s^3) conversion factor between the MS-bar quark mass and the one defined in the so-called Regularization Invariant scheme. The NNNLO contribution in the conversion factor turns out to be relatively large and comparable to the known NNLO term.Comment: 4 pages, Latex, uses espcrc2.sty. The paper is also available via anonymous ftp at ftp://ttpux2.physik.uni-karlsruhe.de/ttp99/ttp99-39/ or via www at http://www-ttp.physik.uni-karlsruhe.de/Preprints
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